In recent years, it has been a critical issue to deal with saving energy in an area of buildings such as residential housing as well as those of home electric appliances and industrial devices from an aspect of environmental conservation. Therefore, an application of various heat insulation materials or various heat insulation construction methods has been suggested (for example, see Reference Patent 1).
FIG. 1 shows an outline cross section diagram of a conventional building 1 disclosed in the Reference Patent 1. As shown in FIG. 1, the conventional building 1 in the Reference Patent 1 maintains a heat insulating property by having rigid polyurethane foam 2 as a heat insulation material, of which heat conductivity is below 0.020 W/mK, in an internal part of an external wall finishing material and a roof material 4.
Since the rigid polyurethane foam 2 has an excellent heat insulating property, it can be available for construction in a thin form. Therefore, when it is used for construction, it does not require a long nail or a screw, and it is possible to use construction nails such as a 15 cm nail that are generally used.
FIG. 2 is a diagram to explain a conventional construction procedure for heat insulation. In the conventional construction procedure for heat insulation, as shown in a perspective cross section diagram for an external wall 1a of the conventional building 1 in FIG. 2, a wooden axis 7 is assembled on a base column 6 of a concrete foundation 5, a structural face material 8 is attached on the wooden axis 7, and then on top of that, a plural number of wooden bases 9a are aligned in parallel in a vertical direction. Additionally, the rigid polyurethane foam 2 is located between the wooden bases 9a, plywood 10 is affixed on the rigid polyurethane foam 2, a plural number of wooden bases 9b are aligned in parallel on the plywood 10 in a vertical direction, and an external wall finishing material 3 is fixed on the wooden base 9b. 
Patent Reference 1: Japanese Laid-Open Patent 2003-278290